The narcissist's positive emotions come bundled with very negative ones. This is the outcome of frustration and the consequent transformations of aggression. This frustration is connected to the Primary Objects of the narcissist's childhood (parents and caregivers).
The narcissist can appreciate beauty but in a cerebral, cold and "mathematical" way. Many have no mature, adult sex drive to speak of. Their emotional landscape is dim and grey, as though through a glass darkly.
Many narcissists can intelligently discuss those emotions never experienced by them -- like empathy, or love -- because they make it a point to read a lot and to communicate with people who claim to be experiencing them. Thus, they gradually construct working hypotheses as to what people feel. As far as the narcissist is concerned, it is pointless to try to really understand emotions -- but at least these models he does form allow him to better predict people's behaviours and adjust to them.
Narcissists are not envious of others for having emotions. They disdain feelings and sentimental people because they find them to be weak and vulnerable and they deride human frailties and vulnerabilities. Such derision makes the narcissist feel superior and is probably the ossified remains of a defence mechanism gone awry.
(From the book "Malignant Self-love: Narcissism Revisited" by Sam Vaknin - Click on this link to purchase: http://www.narcissistic-abuse.com/thebook.html)